It's no secret that obesity in America has reached epidemic proportions. Now, new research shows that children between the ages of 8-15 who are in the upper half of their normal weight range are more likely to become overweight or obese young adults than their leaner counterparts.

Researchers recorded the height, weight and blood pressure of 314 Massachusetts children, ages 8-15 years old at baseline, between 1978 and 1981. These values were measured in the same participants eight to 12 years later at follow-up. Participants averaged a mean body mass index (BMI) of 20 kg/m2 at the first childhood visit, with a "prevalence of at risk for overweight or overweight at the first childhood visit [at] 34 percent for girls and 32 percent for boys."

At follow-up, 48.3 percent of the boys and 23.5 percent of the girls were overweight or obese. High blood pressure was more prominent among the boys (12.3 percent) than girls (1.9 percent), as well. According to the authors, children with a BMI between the national 85th and 95th percentiles for age and gender were classified as at risk for overweight, and those with a BMI > 95th percentile were classified as overweight." The authors considered BMI between the 50th and 84th percentile to be at the high end of a normal weight range.

The researchers concluded, "Although very lean children are unlikely to become overweight adults, we observed that children in the upper end of the healthy weight range (e.g., 50th to 84th percentiles) are at an elevated risk of becoming overweight or obese. Furthermore, boys in the upper end of the healthy weight range are at an increased risk of becoming hypertensive. These findings suggest that future interventions to prevent adult obesity and its complications should include not only overweight children but also children and adolescents as low as the 50th percentile of BMI for age and gender."